Process of treating metal.



Patented Nov. 25, I902.

a. c. mason. PROCESS OF TREATING;- METALS.

(Appliuation filed June 10, 1902.)

(No Model.)

G60 rye C, i /Saw UNITED STATES T ATENT FFIcE.

GEORGE CAMPBELL CARSON, OF BEDDING, CALIFORNIA, ASSIGNOR OF TWO-THIRDS TO FRED HURST, OF REDDING, CALIFORNIA, AND ALBERT MILLER, OF WASHINGTON, DISTRICT OF COLUMBIA.

PROCESS OF TREATING METAL.

SPECIFICATION forming partof Letters Patent No. 714,450, dated November 25, 1902. Application filed June 10, 1902. Serial No. 111,020. (No specimens.)

To all whom it may concern:

Be it known that I, GEORGE CAMPBELL CAR- SON, a citizen of the United States, residing at Bedding, Shasta county, California, have invented certain new and useful Improvements length of time and which could be carried out in asingle apparatus.

Heretofore it has been customary by duplex operations in open-hearth and Bessemer practiceto desiliconize the metal in an acidlined vessel, after which it is poured out and transferred to a basic-lined vessel, where it is treated for the removal of the carbon and phosphorus.

. is Well understood, it has not been generally adopted, owing to the extra equipment required and the necessity for costly installation of new converters or furnaces.

The two-vessel process is open to the further objection that as soon as a certain amount.

of pure metal has accumulated in the bottom of the vesel it must be emptied to prevent loss, I

thus losing valuable time. Furthermore, if the pure metal in the vessel is allowed to rise above the twyer-line it will be subjected to further oxidation by the air-blast, thus resulting in waste of metal and rapid wearing away of the bottom of the vessel due to the action of the oxide of the pure metal contacting with the lining. By my improved process these objections are avoided, as the pure metal is removed continuously and automatically from the bottom of the vesselor chamber as fast as it is formed by the pressure of gravity caused by the inflow of initial metal.

I have illustrated an apparatus for carrying out my improved process in the accompanying drawings, in which- Figure 1 is a transverse section of a converter. Fig. 2 is a longitudinal vertical section of the same. Fig. 3 is a similar view of a modified form.

I11 the figures similar reference-letters indicate the same or like parts wherever used.

A suitable converter is indicated at B and is provided with a series of communicating compartments. Thecompartmentcoccupies the initial end of the converter and receives the molten metal through a suitable inletport 0' from a blast-furnace or other suitable s0urcesuch, for instance, as a molten-metal reservoir. A suitable slag-outlet d and spout d are also provided. A wall or partition separates the compartment 0 from the next com partment j", a communicating passage 9 being provided at the bottom beneath said wall. Compartment fis separated from compartment '5 by a wall containing a port or passage h, to which the molten metal is compelled to rise in compartmentf to find an exit. Y I find in practice that compartmentf can be made comparatively small and, in fact, need be little more than a vertical passage. next compartment Z is separated from compartment 'i by a wall or partition, beneath which is a communicating port or passagej, and compartment 5 is separated from the last compartment m by a wall having a port or passage Z, as shown. This compartment m is provided with a suitable spout mi, discharging into a chill, preferably portable and carried on wheels.

The walls of the converter and its compartments are of suitable refractory material,

and the linings are of a character suitable to the kind of metal under treatment. Thus in converting iron the lining of compartment 0 will be an acid lining, and the linings in compartments f and 2' will be basic linings, so that in all cases they will be neutral to the slags and better withstand the scorifying of the slags.

Oxygen is supplied to the compartments 0 and '1; in the converter shown by twyers a, which are carried horizontally through the converter-walls and which communicate with air headers or trunks .9, extending along the The p sides. As it is desirable to supply such air in a heated condition, it has been usual to employ some external heating apparatus for bringing the air to the proper temperature. One part of my invention relates to the utilizing of the flame produced by blowing airinto molten metal containing carbon or combustible elements in the converter for heating the air-supply previous to its admission to the twyers. I accomplish this by forming an airchamber in the hood c, which is supported above the converter in any suitable way, as by pillars or hangers, and which has an outlet or stack y at any convenient point. For this purpose I prefer the construction shown in Fig. 1, in which the hood has double walls inclosing an air-space and which can be made in the form shown or in any other shape desired, provided that it be properly exposed to the heat below. The double walls should be braced and strengthened, and I have shown for that purpose braces or bolts '0 between the walls. An air-supply pipe q is connected to this heating-chamber, and hot-air-discharge pipes q lead from it and communicate with the headers s, embedded in the walls of the converter. Thus the cold air supplied to the double-walled hood is heated by the molten metal under treatment, and external heating means are entirely done away with.

The double hood is provided with one or more hinged charging-doors 50. When open, such doors form chutes through which iron or steel scrap, oxid of lime, or other fluxes can be supplied to the converter, as may be desired.

It will be seen that the hood is supported so that there is a slight space between its lower edge and the top of the converter. This permits sufficient air to enter beneath the hood during the blowing to convert the car bon monoXid into carbon dioxid.

By reference to Fig. 1, it will be seen that the cross-section of the converter is tapered downwardly-that is, that in cross-section its walls converge toward the bottom. This is for the purpose of protecting the twyers z and at the same time allowing them to project inwardly, so as to discharge practically at the point of greatest efficiency, which is the middle of the bath. It will be noted that the twyers in Fig. 1 do so discharge, but are embedded throughout their lengths in the converter-lining, whereby they are protected not only from the molten metal, but from heavy scrap, fluxes, &c., dumped into the converter. The thick heavy lining thus provided at the bottom not only protects the twyers, but enables the converter to resist for a much longer time the dissolving action of the oxid of iron, thus materially lengthening the lifetime of the converter.

In the event that scrap-iron is not available to prevent an excessively-high temperature I find it desirable to provide a steamgenerator in or under the roof, connected by suitable pipe connections with'the twyers. I prefer to have this in the form of a heatingcoil 0, the uppermost pipe of which, 0, is preferably larger and connects by a pipe 0 with branch pipes 0 leading downward and connecting with the twyers.

In operating the converter and supposing that pig-iron is the metal under treatment, the metal flows into a vessel which is lined with acid material below the twyer-line to the top. The blast is turned on and the vessel is allowed to fill with molten metal, and the oxygen in the blast seizes the silicon and carbon. The silicon is converted into SiO which rises to the surface and forms slag. The carbon becomes 00 in the vessel; but on rising to the top of the converter-walls enough atmospheric oxygen will be admitted underneath the hood to combust the gas to 00 the flame being used to generate steam and preheat the blast, as before described. A layer of slag sufficiently thick to allow all the shot it contains to settle back to the bath will be allowed to form on the surface of the bath before the tap-hole will allow it to discharge through its spout. All the iron below the twyer-line will be desiliconized iron, and as the twyers are discharging their blast above it it will not be subjected to further oxidation, as is the case in a Bessemer converter, where the iron contacting with the orifices of the twyers is when it has given up its combustible contents. This is an important feature, for by my process the life of a bottom will be much longer than one where oxids of the pure metal contact with the bottom, because the metallic oxids are all bases and have strong affinity for silica and are lost. From the channel below the twyer-line the metal is forced through a passage provided at the bottom for its outlet and then upward, where it is delivered into the basic vessehnear the surface. In the basic vessel is added the required lime for dephosphorization, or in case of treating copper or other mattes the required flux may be added to liquefy the oxids of iron that they may be discharged through a tap-hole or spout, and when the pure metal accumulates below the twyer-line in the basic vessel it will be forced by the inflow of metal from the acid vessel into the metal well free from all slags, where it can be tapped into the ingot-molds or recarburized. Here is another important saving in my process at the end of the operation in manufacturing steel: there will be absolutely no slag present to absorb carbon or manganese from the recarburizer,and therefore no phosphorus can be returned to the steel, as is always done in recarburizing in the presence of phosphoric slags.

The process can be operated in connection with any blast-furnace and will require not more than one-third the yard-room which is now required to cast pig-iron and can be installed at much less expense than one open- 1 hearth furnace and will not require any producer or gas plant to operate in conjunction t with it, as sufficient heat will be generated by the combustion of silicon, carbon, manganese, and phosphorus to answer all purposes.

Having thus described my invention, what 1. The herein-described process of treating 1513i} molten metal which consists in feeding the t to molten metal continuously into a suitable and up through a substantially vertical channel whereby a sufficient body of metal is maintained in the vessel, substantially as del scribed.

2. The herein-described method of treating molten metals which consists in feeding the molten metal into a suitable-vessel, subjecting the same to the action of an air-blast delivered to the metal above the bottom of the vessel, allowing the purified metal to fiow by gravity from the bottom of the vessel below the blast-line intothe upper portion of a second vessel, subjecting the metal in said second vessel to a blast of air delivered near the bottom of said vessel, and drawing off the stantially as described.

purified metal by gravity from said second vessel below the line of the ai rblast, sub- 3. The herein-described process of treating m molten metals which consists in feeding the molten metal continuously into a suitable vessel, subjecting such metal to the action of a blast of airdelivered near the bottom, allow- 7 ing the accumulated slagto flow off from the surface of the metal, conveying the purified metal automatically and continuously from the said vessel below the blast-line into the upper part of a second vessel, subjecting the metal in said second vessel to the action of an I air-blast delivered near the bottom of the vessel, allowing the slag to flow off from the surface of the metal, and withdrawing the purified metal from said second vessel below the blast-line, substantially as described.

4. The herein-described process of refining iron which consists in feeding molten iron into an acid vessel continuously, subjecting the metal therein to a blast of air, removing the slag from the surface of the metal, automatically withdrawing the purified iron from below the blast-line and delivering it into the upper part of a basic-lined vessel, subjecting the metal in said second vessel to a blast of air, removing the slag from the surface of the metal and drawing off the purified metal from a point below the blast-line, substantially as described.

5. The herein-described process of refining iron which consists in feeding molten iron into an acid vessel, subjecting the metal therein to a blast of air, removing the slag from the surface of the metal, automatically withdrawing the purified iron from below the blast-line and delivering it into the upper part of a basic-1i ned vessel, subjecting the metal in said second vessel to a blast of air, removing the slag from the surface of the metal, drawing off the purified metal from a point below the blast-line into a third vessel, and recarbonizing the metal in said third vessel, substantially as described.

6. The herein-described process of treating molten metals which consists in supplying the molten metal to a suitable vessel, subjecting the same to an oxidizing blast delivered. near the bottom, supplying sufficient air to the surface of the metal to complete the combustion of the partly-oxidized elements driven off from the metal, and passing the oxidizingblast-into proximity to the flame above the surface of the metal for preheating said blast, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

GEO. CAMPBELL CARSON. Witnesses:

WESLEY TOWNSEND, HENRY F. METZGER. 

